The proposed research has as its objective the further clinical and pathological delineation of cerebral strokes due to thrombosis and hemorrhage. Sixty carotid endarterectomy specimens surgically removed in the treatment of carotid strokes will be studied and the findings correlated with the clinical and radiological observations. This study is to throw light on the mechanism of transient ischemic attacks, the final events of vascular occlusion and the essential characteristics of large artery atheroma. Uninterrupted serial sections of the specimens will be prepared. The clinical and vasculo-pathological features of basilar branch strokes will be continued again using serial sections of brain stem infarcts. The advisability of immediate carotid surgery in the face of recent cerebral infarction in cases of carotid stenosis or occlusion will be assessed by a follow-up clinical study. The vascular lesions underlying capsular infarcts will be pursued using serial sections of the basal ganglia in cases with a capsular infarct. Hypertensive hemorrhages will be serially sectioned attempting to identify the primary site of bleeding. Similarly brain stem secondary hemorrhages associated with tentorial herniation will be studied pathologically attempting to identify the site of bleeding. The mechanism of recovery following hemiplegia will be investigated by a clinico-pathologic study of patients with successive strokes involving first one then the other side of the body.